Object-oriented interactive modeling for virtual environments

This paper presents the use of object-oriented programming paradigm, such as C++, for the natural and flexible specification of interactive modeling process. The top level of our modeling hierarchy is divided into two basic collections: geometric forms and interactive devices. In the geometry superclass, three classes-ListItem, CircItem, and CircList-are defined as a class-type structure that can be dynamically inserted and deleted upon the user´s interactions in real time. Class ListItem, as an item abstraction, is further derived to several primitive subclasses whose instances can be combined into various geometrical forms. The interactive device superclass, on the other hand, is currently derived into two typical interactive devices: keyboard and mouse. Their behaviors specify the two basic interactive control functionalities: states and 3D movement sensing, which can be similarly defined for the virtual device subclasses such as 3D mouse and DataGlove. The class-modeling prototype defined in our system has been experimented for the interactive modeling of multiple room environments with objects placed within them